Tribological Aspects of Thermally Sprayed Red Mud-Fly Ash and Red Mud-Al Coatings on Mild Steel

The present research work explains the dry sliding wear characteristics of thermally sprayed red mud and its composite coatings. Composite of red mud, fly ash and aluminium are plasma sprayed at 6, 9, 12 and 15 kW operating power levels. The coatings were experimented to study the tribological behaviour like dry sliding wear behaviour, XRD phase transformation, coating thickness, coating morphology, wear morphology, wear mechanism and co-efficient of friction. 10% Fly ash and 5% aluminium powder were mixed separately by weight with pure red mud and sliding wear test was conducted using pin on disc wear test machine. The test was performed with track diameter of 100 mm and at sliding speed of 100 rpm (0.523 m/s) at a normal load of 20 N. Coating property was discriminated by variation of sliding time length. Operating power was found to be remarkable variable for wear rate, coating thickness, coating morphology and friction coefficient. Significant increase in wear resistance was observed with fly ash and aluminium addition, resulting in an increase in interfacial bond strength and dense film formation.